#include<iostream>
#include<cstring>
#include<vector>
#include<array>
#include<cassert>
#include<algorithm>
using namespace std;
using LL = long long;
const int maxn = 2e6 + 5, mod = 998244353, G = 3, Gi = 332748118;

int qpow(int a, int b, int mod){
    int res = 1;
    while (b){
        if (b & 1) res = 1LL * res * a % mod;
        a = 1LL * a * a % mod;
        b >>= 1;
    }
    return res;
}

inline int mul(int a, int b){
    return 1LL * a * b % mod;
}

inline void add(int &a, int b){
    a += b;
    if (a >= mod) a -= mod;
}

inline void sub(int &a, int b){
    a -= b;
    if (a < 0) a += mod;
}

namespace NTT{
    vector<int> Omega(int L){
        int wn = qpow(G, mod / L, mod);
        vector<int> w(L); 
        w[L >> 1] = 1;
        for(int i = L / 2 + 1; i < L; i++) w[i] = mul(w[i - 1], wn);
        for(int i = L / 2 - 1; i >= 1; i--) w[i] = w[i << 1];
        return w;
    }
    auto W = Omega(1 << 21);

    void DIF(int *a, int n) {
        for(int k = n >> 1; k; k >>= 1)
            for(int i = 0, y; i < n; i += k << 1)
                for(int j = 0; j < k; j++){
                    y = a[i + j + k], a[i + j + k] = mul(a[i + j] - y + mod, W[k + j]), 
                    add(a[i + j], y);
                }
    }

    void IDIT(int *a, int n) {
        for (int k = 1; k < n; k <<= 1)
            for (int i = 0, x, y; i < n; i += k << 1)
                for(int j = 0; j < k; j++){
                    x = a[i + j], y = mul(a[i + j + k], W[k + j]),
                    a[i + j + k] = x - y < 0 ? x - y + mod : x - y;
                    add(a[i + j], y);
                }
        int inv = mod - (mod - 1) / n;
        for(int i = 0; i < n; i++) a[i] = mul(a[i], inv);
        reverse(a + 1, a + n);
    }
}

using Poly = std::vector<int>;

void DFT(Poly &a){
    NTT::DIF(a.data(), a.size());
}

void IDFT(Poly &a){
    NTT::IDIT(a.data(), a.size());
}

int normed(int n) { 
    return n == 1 ? 1 : (1 << (32 - __builtin_clz(n - 1))); 
}

void norm(Poly &a) { 
    if (!a.empty()) a.resize(normed((int)a.size()), 0); 
}

void dot(Poly &a, Poly &b) {
    for(int i = 0; i < a.size(); i++)
        a[i] = mul(a[i], b[i]);
}

Poly operator*(Poly a, Poly b) {
    int n = a.size() + b.size() - 1, L = normed(n);
    if (a.size() <= 8 || b.size() <= 8) {
        Poly c(n);
        for(int i = 0; i < a.size(); i++)
            for(int j = 0; j < b.size(); j++)
                c[i + j] = (c[i + j] + 1LL * a[i] * b[j]) % mod;
        return c;
    }
    a.resize(L), b.resize(L);
    DFT(a), DFT(b), dot(a, b), IDFT(a);
    return a.resize(n), a;
}

int C[51][51];

int a[1010], b[1010], c[1010];

bool v[1010][10][2][2];
array<int, 50> f[1010][10][2][2];

int pow10[1010], pows[51], inv[51], fact[51], invfact[51];

int k;

void update(array<int, 50> &ans, const array<int, 50> &t, int val){
    pows[0] = 1;
    for(int i = 1; i < k; i++) pows[i] = mul(pows[i - 1], val);
    vector<int> a(k), b(k);
    for(int i = 0; i < k; i++){
        a[i] = mul(invfact[i], t[i]);
        b[i] = mul(invfact[i], pows[i]);
    }
    a = a * b;
    
    for(int i = 0; i < k; i++){
        add(ans[i], mul(fact[i], a[i]));
    }
}

array<int, 50> e;

// 当前位数, lim, 是否需要往上借位, 是否全是前导零

array<int, 50> dfs(int u, int last, bool flag, bool lead){
    if (u == 0){
        return flag ? array<int, 50>{} : e;
    }
    if (lead) last = 9;
    if (v[u][last][flag][lead]) return f[u][last][flag][lead];
    v[u][last][flag][lead] = true;
    const int up = 9;
    array<int, 50> ans{};
    if (flag){
        for(int i = 0; i <= up and i <= b[u]; i++){
            int r = i + 10 - b[u];
            if (i <= last) update(ans, dfs(u - 1, i, 1, lead and (i == 0)), mul(r - 1, pow10[u - 1]));
            if (r < 10 and i <= last){
                update(ans, dfs(u - 1, i, 0, lead and (i == 0)), mul(r, pow10[u - 1]));
            }
        }
    }
    else{
        for(int i = b[u]; i <= up; i++){
            int r = i - b[u];
            if (i <= last) update(ans, dfs(u - 1, i, 0, lead and (i == 0)), mul(r, pow10[u - 1]));
            if (r - 1 >= 0 and i <= last){
                update(ans, dfs(u - 1, i, 1, lead and (i == 0)), mul(r - 1, pow10[u - 1]));
            }
        }
    }
    return f[u][last][flag][lead] = ans;
}

int main(){

#ifdef LOCAL
    freopen("data.in", "r", stdin);
    freopen("data.out", "w", stdout);
#endif

    cin.tie(0);
    cout.tie(0);
    ios::sync_with_stdio(0);

    for(int i = 0; i <= 50; i++){
        for(int j = 0; j <= i; j++){
            if (!j) C[i][j] = 1;
            else C[i][j] = (C[i - 1][j - 1] + C[i - 1][j]) % mod;
        }
    }

    inv[1] = 1;
    for(int i = 2; i <= 50; i++){
        inv[i] = mul(mod - mod / i, inv[mod % i]);
    }
    fact[0] = 1;
    for(int i = 1; i <= 50; i++){
        fact[i] = mul(fact[i - 1], i);
    }
    invfact[0] = 1;
    for(int i = 1; i <= 50; i++){
        invfact[i] = mul(invfact[i - 1], inv[i]);
    }

    string L, R;
    cin >> L >> R;
    int pos = R.size() - 1;
    while(pos >= 0 and R[pos] == '9') pos--;
    if (pos == -1){
        R = "1" + string(R.size(), '0');
    }
    else{
        R[pos] += 1;
        for(int i = pos + 1; i < R.size(); i++){
            R[i] = '0';
        }
    }

    cin >> k;
    e[0] = 1;
    for(int i = 1; i < k; i++){
        e[i] = mul(e[i - 1], k - 1);
    }
    pow10[0] = 1;
    for(int i = 1; i < 1010; i++){
        pow10[i] = mul(pow10[i - 1], 10);
    }

    int sum = 0;
    for(int cnt = 0; cnt <= k; cnt++){
        memset(b, 0, sizeof b);
        for(int i = 0; i < L.size(); i++){
            b[L.size() - i] += (L[i] - '0') * (k - cnt);
        }
        for(int i = 0; i < R.size(); i++){
            b[R.size() - i] += (R[i] - '0') * cnt;
        }
        for(int i = 1; i + 1 < 1010; i++){
            b[i + 1] += b[i] / 10;
            b[i] %= 10;
        }
        memset(v, 0, sizeof v);
        auto ans = dfs(R.size() + 3, 9, false, true);
        int sign = mul(cnt % 2 == 0 ? 1 : mod - 1, C[k][cnt]);
        int c[50]{};
        c[0] = 1;
        for(int j = 0; j < k - 1; j++){
            int nc[50]{};
            for(int t = 0; t < 50; t++){
                if (t + 1 < 50) add(nc[t + 1], c[t]);
                add(nc[t], mul(c[t], mod - j));
            }
            swap(c, nc);
        }
        int t = 0;
        for(int i = 0; i < k; i++){
            add(t, mul(ans[i], c[i]));
        }
        for(int i = 1; i <= k - 1; i++){
            t = mul(t, inv[i]);
        }
        add(sum, mul(sign, t));
    }
    cout << sum << '\n';

}