#include <cstdio>

using namespace std;

inline int Ok(int a, int b, int c)
{
    if((a+b<c) || (b+c<a) || (c+a<b))
        return 0;
    return 1;
}

int main()
{
    int i,j,k,N,v[1000],sol=0;
    freopen ("nrtri.in","r",stdin);
    freopen ("nrtri.out","w",stdout);
    scanf("%d", &N);
    for(i=1;i<=N;++i)
        scanf("%d", &v[i]);

    for(i=1;i<N-1;++i)
        for(j=i+1;j<N;++j)
            for(k=j+1;k<=N;++k)
                sol+=Ok(v[i],v[j],v[k]);
    printf("%d\n", sol);
    return 0;
}