#include <bits/stdc++.h>
// #include "atcoder/modint"

using i64 = long long;
// using Fp = atcoder::modint998244353;

int main() {
    int N, Q;
    std::cin >> N >> Q;
    std::vector<i64> C(2 * N + 1);
    for (int i = 1; i <= N; ++i) {
        std::cin >> C[i];
    }

    std::vector<i64> L(Q), D(Q);
    for (int i = 0; i < Q; ++i) {
        std::cin >> L[i] >> D[i];
    }

    for (int q = 0; q < Q; ++q) {
        C[L[q]] += D[q];

        i64 ans = 0;
        int l = 1;
        auto X = C;
        for (int i = 1; i <= N; ++i) {
            while (true) {
                if (X[i] < 2) break;
                while (l != 2 * i and (X[l] == 0 or (l == i and X[l] < 3))) ++l;
                if (l == 2 * i) break;
                i64 k = i == l ? X[i] / 3 : std::min(X[i] / 2, X[l]);
                X[i] -= 2 * k;
                X[l] -= k;
                ans += k;
            }
        }
        std::cout << ans << std::endl;
    }
}