#include <bits/stdc++.h>   using namespace std;   const long long dx[] = {-1, 0, 0, 1};   const long long dy[] = {0, -1, 1, 0};   const int Mass = (int)2e5 + 5;   const int inf = (int)1e9 + 5;   const long long linf = (long long)1e18 + 5;   const long long Mod = (long long)1e9 + 7;   long long ModFix(long long a, long long Mod) {     return ((((a) % (Mod)) + (Mod)) % (Mod));   }   long long ModSum(long long a, long long b, long long Mod) {     return ModFix(((a) + (b)), (Mod));   }   long long ModSub(long long a, long long b, long long Mod) {     return ModFix(((a) - (b)), (Mod));   }   long long ModMul(long long a, long long b, long long Mod) {     return ModFix(((a) * (b)), (Mod));   }   int a[150];   int main() {     ios_base ::sync_with_stdio(false);     cin.tie(NULL);     int n, m;     cin >> n;     cin >> m;     int res = 0;     for (int i = 1; i <= n; ++i) cin >> a[i];     for (int i = 1; i <= m; ++i) {       int l, r;       cin >> l >> r;       int sum = 0;       for (int j = l; j <= r; ++j) {         sum += a[j];       }       if (sum >= 0) res += sum;     }     cout << res;     return 0;   }   