#include <cstdio>
#define rep(i, d, u) for(int i = d; i <= u; ++i)
#define dep(i, u, d) for(int i = u; i >= d; --i)
#define gep(i, a) for(int i = firs[a]; i; i = neig[i])
int ured() {
	int re = 0;
	char ch;
	do {
		ch = getchar();
	} while('9' < ch || ch < '0');
	do {
		re = re * 10 + (ch ^ '0');
	} while('0' <= (ch = getchar()) && ch <= '9');
	return re;
}
void sred(bool *st) {
	int re = 0;
	char ch;
	do {
		ch = getchar();
	} while(ch != '0' && ch != '1');
	do {
		st[++re] = ch ^ '0';
	} while((ch = getchar()) == '0' || ch == '1');
}
void uwit(int da) {
	int ch[21], cn = 0;
	do {
		ch[++cn] = da - da / 10 * 10;
	} while(da /= 10);
	do {
		putchar('0' ^ ch[cn]);
	} while(--cn);
}
int max(int le, int ri) {
	return le > ri ? le : ri;
}
const int _maxn = 500011;
int n, q, l[_maxn], r[_maxn], p[_maxn], firs[_maxn], neig[_maxn], rans[_maxn], lans[_maxn], lenr[_maxn], lpos;
int nexa[_maxn], prea[_maxn], nexb[_maxn], fatp[_maxn], fath[_maxn], sizs[_maxn], fats[_maxn << 1], prel[_maxn], regl[_maxn];
bool s[_maxn];
int find(int at) {
	if(fath[at] == at) {
		return at;
	} else {
		int re = find(fath[at]);
		sizs[at] += sizs[fath[at]];
		return fath[at] = re;
	}
}
int fids(int at) {
	return fats[at] == at ? at : fats[at] = fids(fats[at]);
}
int main() {
	lenr[0] = n = ured(), q = ured(), sred(s);
	rep(i, 1, q) {
		l[i] = ured(), r[i] = ured(), p[i] = ured(), neig[i] = firs[p[i]], firs[p[i]] = i;
	}
	rep(i, 1, n) {
		if(i == n || s[i] ^ s[i + 1]) {
			prea[nexa[lpos] = i] = lpos, fatp[i] = lpos + 1, lpos = fath[i] = i, sizs[i] = 0, lpos = fath[i] = i, prel[i] = i;
		} else {
			nexb[i] = fath[i] = i + 1, sizs[i] = 1;
		}
		fats[i] = i;
	}
	nexa[lpos] = 0;
	rep(i, 1, q) {
		fats[n + 1 + i] = r[i];
	}
	rep(i, 0, n) {
		gep(j, i) {
			int po = fids(n + 1 + j);
			rans[j] = prel[find(po)] - sizs[po];
		}
		for(int j = nexa[0]; j; j = nexa[j]) {
			regl[j] = prel[j] - prel[prea[j]];
		}
		for(int j = nexa[0]; j; j = nexa[j]) {
			fats[fatp[j]] = prea[j], --regl[j];
			if(fatp[j] == j) {
				if(nexa[prea[j]] = nexa[j]) {
					prea[nexa[j]] = prea[j];
				}
			} else {
				fatp[j] = nexb[fatp[j]];
				if(prea[j] && s[j] == s[prea[j]]) {
					if(nexa[prea[j]] = nexa[j]) {
						prea[nexa[j]] = prea[j];
					}
					sizs[j] = 1, nexb[j] = fath[j] = fatp[prea[j]], fatp[prea[j]] = fatp[j], regl[prea[j]] += regl[j];
				}
			}
		}
		for(int j = nexa[0]; j; j = nexa[j]) {
			lenr[i + 1] = prel[j] = prel[prea[j]] + regl[j];
		}
	}
	lpos = n + 1;
	dep(i, n, 1) {
		if(i == 1 || s[i] ^ s[i - 1]) {
			prea[nexa[lpos] = i] = lpos, fatp[i] = lpos - 1, lpos = fath[i] = i, sizs[i] = 0, lpos = fath[i] = i, prel[i] = n - i + 1;
		} else {
			nexb[i] = fath[i] = i - 1, sizs[i] = 1;
		}
		fats[i] = i;
	}
	nexa[lpos] = 0;
	rep(i, 1, q) {
		fats[n + 1 + i] = l[i];
	}
	rep(i, 0, n) {
		gep(j, i) {
			int po = fids(n + 1 + j);
			lans[j] = prel[find(po)] - sizs[po];
		}
		for(int j = nexa[n + 1]; j; j = nexa[j]) {
			regl[j] = prel[j] - prel[prea[j]];
		}
		for(int j = nexa[n + 1]; j; j = nexa[j]) {
			fats[fatp[j]] = prea[j], --regl[j];
			if(fatp[j] == j) {
				if(nexa[prea[j]] = nexa[j]) {
					prea[nexa[j]] = prea[j];
				}
			} else {
				fatp[j] = nexb[fatp[j]];
				if(prea[j] <= n && s[j] == s[prea[j]]) {
					if(nexa[prea[j]] = nexa[j]) {
						prea[nexa[j]] = prea[j];
					}
					sizs[j] = 1, nexb[j] = fath[j] = fatp[prea[j]], fatp[prea[j]] = fatp[j], regl[prea[j]] += regl[j];
				}
			}
		}
		for(int j = nexa[n + 1]; j; j = nexa[j]) {
			prel[j] = prel[prea[j]] + regl[j];
		}
	}
	rep(i, 1, q) {
		uwit(max(lans[i] + rans[i] - lenr[p[i]], 0)), putchar('\n');
	}
	return 0;
}