#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#define rep(i,j,k) for(int i=(j);i<=(k);i++)
#define per(i,j,k) for(int i=(j);i>=(k);i--)
#define uint unsigned int
#define ll long long
#define ull unsigned long long
#define db double
#define ldb long double
#define pii pair<int,int>
#define pll pair<ll,ll>
#define mkp make_pair
#define eb emplace_back
#define SZ(S) (int)S.size()
//#define mod 998244353
//#define mod 1000000007
#define inf 0x3f3f3f3f
#define linf 0x3f3f3f3f3f3f3f3f
using namespace std;

template <class T>
void chkmax(T &x,T y){
	if(x < y) x = y;
}

template <class T>
void chkmin(T &x,T y){
	if(x > y) x = y;
}

inline int popcnt(int x){
	return __builtin_popcount(x);
}

inline int ctz(int x){
	return __builtin_ctz(x);
}


/*ll power(ll p,int k = mod - 2){
	ll ans = 1;
	while(k){
		if(k % 2 == 1) ans = ans * p % mod;
		p = p * p % mod;
		k /= 2;	
	}
	return ans;
}*/
int n,m,k;
char s[1000005];
int a[1000005],b[1000005],c[1000005];

vector <pii> answer;
int top;
int stk[1000005];
void psh(int v){
//	printf("psh %d\n",v);
	stk[++top] = v;
}
int pick(){
	assert(top);
	return stk[top--];
}
void clr(int l,int r){
//	printf("clr [%d,%d]\n",l,r);
	assert(r > l);
	if(l % 2 == r % 2){
		answer.eb(l,3);
		r -= 3;
	}
	while(l <= r){
		answer.eb(l,2);
		r -= 2;
	}
}
int dp[6005][6005];
int main(){
//	freopen("test.in","r",stdin);
	scanf("%d",&n);
	scanf("%s",s + 1);
	for(int l = 1,r;l <= n;l = r + 1){
		r = l;
		while(r < n && s[r] == s[r + 1]) r++;
		a[++m] = r - l + 1;
	}

	k = 0;
	rep(i,1,m){
		if(a[i] == 1) b[k]++;
		else c[++k] = a[i];
	}
	if(!k){
		printf("-1\n");
		return 0;
	}
	memset(dp,0,sizeof(dp));
	dp[0][b[0]] = 1;
	rep(i,1,k - 1){
		rep(x,0,m){
			if(!dp[i - 1][x]) continue;
			if(b[i] - x >= 0) dp[i][b[i] - x] = 1;
			rep(y,max(b[i] + 1 - x,x - (b[i] + 1)),b[i] + 1 + x) if((x + y) % 2 != b[i] % 2) dp[i][y] = 1;
		}
	}
/*	rep(i,1,m) printf("%d ",a[i]);
	printf("\n");
	rep(i,0,k) printf("%d ",b[i]);
	printf("\n");
	rep(i,1,k) printf("%d ",c[i]);
	printf("\n");*/
	if(!dp[k - 1][b[k]]){
		printf("-1\n");
		return 0;
	}
	rep(i,1,b[k]) psh(1);
	int x = b[k],y,aa,bb,sum = n - b[k];
	per(i,k - 1,0){
		y = x;x = aa = bb = -1;
		if(i){
			rep(xx,0,m){
				if(!dp[i - 1][xx]) continue;
				if(b[i] - xx == y){
					x = xx;
					aa = x;
					bb = y;
				}
				rep(yy,max(b[i] + 1 - xx,xx - (b[i] + 1)),b[i] + 1 + xx){
					if((xx + yy) % 2 != b[i] % 2 && yy == y){
//						printf("transfer %d->%d ok\n",xx,yy);
						x = xx;
						aa = (b[i] + 1 + x - y) / 2;
						bb = (b[i] + 1 - x + y) / 2;
					}
				}
			}			
		}else{
			x = 0;
			bb = b[i];
		}
//		printf("i=%d y=%d chose x=%d bb=%d sum=%d\n",i,y,x,bb,sum);
		assert(x != -1);
		assert(bb <= b[i] + 1);
		sum -= c[i + 1];
		psh(c[i + 1]);
		rep(kk,1,bb){
			clr(sum + 1,sum + pick());
			if(kk != b[i] + 1){
				stk[top]++;
				sum--;
			}else{
				sum -= c[i];
				c[i] += pick();
				sum += c[i];
			}
		}
		rep(kk,1,b[i] - bb){
			psh(1);
			sum--;
		}
	}
	while(top) clr(1,stk[top--]);
	printf("%d\n",SZ(answer));
	for(pii I:answer) printf("%d %d\n",I.first,I.second);
	return 0;
}