#include <iostream>
#include <cmath>
#include <cstdio>
#include <algorithm>
using namespace std;
int n ,m ,a[5000010], b[5000010];
int x, y, z, minn = 0x3f3f3f;
void insert(int l, int r, int x)
{
    b[l] += x;
    b[r + 1] -= x;
}
inline int read()
{
    int x=0,f=1;
    char ch=getchar();
    while(ch<'0'||ch>'9')
    {
        if(ch=='-')
            f=-1;
        ch=getchar();
    }
    while(ch>='0' && ch<='9')
        x=x*10+ch-'0',ch=getchar();
    return x*f;
}
int main()
{ 
    n = read();
    m = read();
    for (int i = 1;i <= n;i ++) a[i] = read(),insert(i, i, a[i]);
    for (int i = 1;i <= m;i ++)
    {
        x = read();y = read();z = read();
        insert(x, y, z);
    }
    for (int i = 1;i <= n;i ++) b[i] += b[i - 1], minn = min(minn, b[i]);
    printf("%d\n", minn);
    return 0;
}