i was trying to solve this cool cses problem the other minute and i stumbled across a problem relating modulo: im pretty sure there is nothing wrong with my usage of spoiler dirichlet's hyperbola method, basically what i did was computing the first two sums modulo M then subtracting the last chunk modulo then modulo the actual result applying the rule (a mod m) — (b mod m) mod m = (a — b mod m), but there is a case when b mod m is just greater than a mod m and not b > a, i don't know what to do! can anyone please correct my usage of modulo! thanks in advance :3

#include <bits/stdc++.h>

using namespace std;
#define int unsigned long long

int G(int n) {
  return n*(n+1)/2;
}

signed main() {
  int n; cin >> n;
  int res = 0, MOD = 1e9 + 7, t = (int)sqrt(n);
  for(int i = 1; i <= t ; i++) {
    res += G(n/i)%MOD;
    res += (i * (n/i))%MOD;
    res %= MOD;
  }

  res -= (G(t)*t)%MOD;
  res %= MOD;
  cout << res;
}