#include
#include

int main()
{
    int i, j, n, n2, sc[100000], co[100000]={0}, small=-999999999;
    scanf("%d %d", &n, &n2);
    for(i=0; i    {
        scanf("%d", &sc[i]);
    }
    for(i=0; i    {
        for(j=i; j        {
            co[i]+=sc[j];
        }
    }
    for(i=0; i    {
        if(co[i]>small)
            small=co[i];
    }
    printf("%d", small);
    return 0;
}