#include <cassert>
#include <cmath>
#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <functional>
#include <iostream>
#include <limits>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <utility>
#include <vector>

using namespace std;

using Int = long long;

template <class T1, class T2> ostream &operator<<(ostream &os, const pair<T1, T2> &a) { return os << "(" << a.first << ", " << a.second << ")"; };
template <class T> ostream &operator<<(ostream &os, const vector<T> &as) { const int sz = as.size(); os << "["; for (int i = 0; i < sz; ++i) { if (i >= 256) { os << ", ..."; break; } if (i > 0) { os << ", "; } os << as[i]; } return os << "]"; }
template <class T> void pv(T a, T b) { for (T i = a; i != b; ++i) cerr << *i << " "; cerr << endl; }
template <class T> bool chmin(T &t, const T &f) { if (t > f) { t = f; return true; } return false; }
template <class T> bool chmax(T &t, const T &f) { if (t < f) { t = f; return true; } return false; }
#define COLOR(s) ("\x1b[" s "m")

////////////////////////////////////////////////////////////////////////////////
template <unsigned M_> struct ModInt {
  static constexpr unsigned M = M_;
  unsigned x;
  constexpr ModInt() : x(0U) {}
  constexpr ModInt(unsigned x_) : x(x_ % M) {}
  constexpr ModInt(unsigned long long x_) : x(x_ % M) {}
  constexpr ModInt(int x_) : x(((x_ %= static_cast<int>(M)) < 0) ? (x_ + static_cast<int>(M)) : x_) {}
  constexpr ModInt(long long x_) : x(((x_ %= static_cast<long long>(M)) < 0) ? (x_ + static_cast<long long>(M)) : x_) {}
  ModInt &operator+=(const ModInt &a) { x = ((x += a.x) >= M) ? (x - M) : x; return *this; }
  ModInt &operator-=(const ModInt &a) { x = ((x -= a.x) >= M) ? (x + M) : x; return *this; }
  ModInt &operator*=(const ModInt &a) { x = (static_cast<unsigned long long>(x) * a.x) % M; return *this; }
  ModInt &operator/=(const ModInt &a) { return (*this *= a.inv()); }
  ModInt pow(long long e) const {
    if (e < 0) return inv().pow(-e);
    ModInt a = *this, b = 1U; for (; e; e >>= 1) { if (e & 1) b *= a; a *= a; } return b;
  }
  ModInt inv() const {
    unsigned a = M, b = x; int y = 0, z = 1;
    for (; b; ) { const unsigned q = a / b; const unsigned c = a - q * b; a = b; b = c; const int w = y - static_cast<int>(q) * z; y = z; z = w; }
    assert(a == 1U); return ModInt(y);
  }
  ModInt operator+() const { return *this; }
  ModInt operator-() const { ModInt a; a.x = x ? (M - x) : 0U; return a; }
  ModInt operator+(const ModInt &a) const { return (ModInt(*this) += a); }
  ModInt operator-(const ModInt &a) const { return (ModInt(*this) -= a); }
  ModInt operator*(const ModInt &a) const { return (ModInt(*this) *= a); }
  ModInt operator/(const ModInt &a) const { return (ModInt(*this) /= a); }
  template <class T> friend ModInt operator+(T a, const ModInt &b) { return (ModInt(a) += b); }
  template <class T> friend ModInt operator-(T a, const ModInt &b) { return (ModInt(a) -= b); }
  template <class T> friend ModInt operator*(T a, const ModInt &b) { return (ModInt(a) *= b); }
  template <class T> friend ModInt operator/(T a, const ModInt &b) { return (ModInt(a) /= b); }
  explicit operator bool() const { return x; }
  bool operator==(const ModInt &a) const { return (x == a.x); }
  bool operator!=(const ModInt &a) const { return (x != a.x); }
  friend std::ostream &operator<<(std::ostream &os, const ModInt &a) { return os << a.x; }
};
////////////////////////////////////////////////////////////////////////////////

constexpr unsigned MO = 998244353;
using Mint = ModInt<MO>;

constexpr int LIM_INV = 110;
Mint inv[LIM_INV], fac[LIM_INV], invFac[LIM_INV];

void prepare() {
  inv[1] = 1;
  for (int i = 2; i < LIM_INV; ++i) {
    inv[i] = -((Mint::M / i) * inv[Mint::M % i]);
  }
  fac[0] = invFac[0] = 1;
  for (int i = 1; i < LIM_INV; ++i) {
    fac[i] = fac[i - 1] * i;
    invFac[i] = invFac[i - 1] * inv[i];
  }
}
Mint binom(Int n, Int k) {
  if (n < 0) {
    if (k >= 0) {
      return ((k & 1) ? -1 : +1) * binom(-n + k - 1, k);
    } else if (n - k >= 0) {
      return (((n - k) & 1) ? -1 : +1) * binom(-k - 1, n - k);
    } else {
      return 0;
    }
  } else {
    if (0 <= k && k <= n) {
      assert(n < LIM_INV);
      return fac[n] * invFac[k] * invFac[n - k];
    } else {
      return 0;
    }
  }
}


/*
  problem
    count (a[1], ..., a[K]) s.t.
      - L <= a[i] <= R
      - digits of (a[1] + ... + a[K]): non-incr. from highest to lowest
*/

int LLen, RLen;
char L[1010], R[1010];
int K;

Mint dp[1010][2][10][50];
Mint bnss[10][50];

int main() {
  prepare();
  
  for (; ~scanf("%s%s%d", L, R, &K); ) {
    LLen = strlen(L);
    RLen = strlen(R);
    reverse(L, L + LLen);
    reverse(R, R + RLen);
    const int len = RLen + 3;
    
    vector<Mint> ten(len + 1);
    ten[0] = 1;
    for (int i = 1; i <= len; ++i) ten[i] = ten[i - 1] * 10;
    
    Mint ans = 0;
    for (int k = 0; k <= K; ++k) {
      // <= (K-k) R + k (L-1)
      vector<int> ms(len, 0);
      for (int i = 0; i < RLen; ++i) ms[i] += (K - k) * (R[i] - '0');
      for (int i = 0; i < LLen; ++i) ms[i] += k * (L[i] - '0');
      ms[0] -= k;
      for (int i = 0; i < len - 1; ++i) {
        int q = ms[i] / 10;
        int r = ms[i] % 10;
        if (r < 0) {
          --q;
          r += 10;
        }
        ms[i + 1] += q;
        ms[i] = r;
      }
      int top = -1;
      for (int i = 0; i < len; ++i) if (ms[i]) top = i;
// cerr<<"k = "<<k<<": ms = "<<ms<<endl;
      
      // (pos, smaller, last, l) -> \sum[b: valid sum] binom(-b,l)
      memset(dp, 0, sizeof(dp));
      for (int i = len; --i >= 0; ) {
        for (int x = 0; x < 10; ++x) {
          bnss[x][0] = 1;
          for (int l = 1; l <= K-1; ++l) {
            bnss[x][l] = bnss[x][l - 1] * (-ten[i] * x + 1 - l) * inv[l];
          }
        }
        for (int s = 0; s < 2; ++s) {
          for (int x = 0; x < 10; ++x) if (s || x <= ms[i]) {
            const int ss = (s || x < ms[i]) ? 1 : 0;
            for (int l = 0; l <= K-1; ++l) for (int dl = 0; l + dl <= K-1; ++dl) {
              dp[i][ss][x][l + dl] += dp[i + 1][s][x][l] * bnss[x][dl];
            }
          }
        }
        // start
        for (int x = 0; x < 10; ++x) if (i < top || x <= ms[i]) {
          const int ss = (i < top || x < ms[i]) ? 1 : 0;
          for (int dl = 0; dl <= K-1; ++dl) {
            dp[i][ss][x][dl] += bnss[x][dl];
          }
        }
        // decrease last
        for (int s = 0; s < 2; ++s) {
          for (int x = 10; --x >= 1; ) {
            for (int l = 0; l <= K-1; ++l) {
              dp[i][s][x - 1][l] += dp[i][s][x][l];
            }
          }
        }
      }
      // binom(m-b+K-1, K-1) ways
      Mint m = 0;
      for (int i = len; --i >= 0; ) (m *= 10) += ms[i];
      m += (K-1);
      Mint here = 0;
      for (int s = 0; s < 2; ++s) {
        Mint bn = 1;
        for (int l = 0; l <= K-1; ++l) {
          here += bn * dp[0][s][0][K-1 - l];
          bn *= (m - l);
          bn *= inv[1 + l];
        }
      }
cerr<<k<<": "<<here<<endl;
      ans += binom(K, k) * (k&1?-1:+1) * here;
    }
    printf("%u\n", ans.x);
  }
  return 0;
}