#include <bits/stdc++.h>
using namespace std;

using i64 = long long;
int n, q, len;

const i64 base1 = 2e7 + 1, base2 = 2e7 + 3;
const i64 mod1 = 1e9 + 7, mod2 = 1e9 + 9;

i64 pw1[1000010], pw2[1000010];
i64 sm1[1000010], sm2[1000010];

int main() {
  scanf("%d%d", &n, &q);

  pw1[0] = pw2[0] = 1;
  for (int i = 1; i <= n; i ++) {
    pw1[i] = pw1[i - 1] * base1 % mod1;
    pw2[i] = pw2[i - 1] * base2 % mod2;
  }
  for (int i = 1; i <= n; i ++) {
    sm1[i] = (sm1[i - 1] + pw1[i - 1]) % mod1;
    sm2[i] = (sm2[i - 1] + pw2[i - 1]) % mod2;
  }

  map<pair<int, int>, int> ans;
  int cur1 = 0, cur2 = 0;
  ans[{cur1, cur2}] = 0;

  for (int id = 1; id <= q; id ++) {
    char op;
    scanf(" %c", &op);
    if (op == '!') {
      int l, r, x;
      scanf("%d%d%d", &l, &r, &x);

      cur1 = (cur1 + (sm1[r] - sm1[l] + mod1) % mod1 * x % mod1 + mod1) % mod1;
      cur2 = (cur2 + (sm2[r] - sm2[l] + mod2) % mod2 * x % mod2 + mod2) % mod2;

      if (ans.find({cur1, cur2}) == ans.end())
        ans[{cur1, cur2}] = id;
    } else {
      printf("%d\n", ans[{cur1, cur2}]);
    }
  }
  return 0;
}