#include <stdio.h>

int combina( int n, int k )
{
    if( n < 0 || k < 0 || k > n )
        return 0;
    int comb = 1, i;
    int kMax, kMin;
    if( k > n/2 )
        kMax = k;
    else
        kMax = n-k;
    for( i = n; i > kMax; i-- )
    {
        comb *= i;
        comb /=( n-i+1 );
    }
    return comb;
}
void leeEntrada( int *n, int *m, int *k1, int *k2, int *k3 )
{
    FILE *inn = fopen( "input.txt", "rt" );
    fscanf( inn, "%d %d\n", n, m );
    fscanf( inn, "%d %d %d", k1, k2, k3 );
    fclose( inn );
}

void escribeSalida( int total )
{
    FILE *outt = fopen( "output.txt", "wt" );
    fprintf( outt, "%d", total );
    fclose( outt );
}

int main()
{
    int n, m, k1, k2, k3;
    leeEntrada( &n, &m, &k1, &k2, &k3 );
    // Contamos las formas de sumar a + b + c = n con a >= k1, b >= k2 y c >= k3
    int total = combina( n + 2 - k1 - k2 - k3, 2 );
    // Le restamos las combinaciones inválidas, es decir a > m, b > m, c > m
    total -= combina( n + 2 - (m+1) - k2 - k3, 2 );
    total -= combina( n + 2 - k1 - (m+1) - k3, 2 );
    total -= combina( n + 2 - k1 - k2 - (m+1), 2 );

    escribeSalida( total );
    return 0;
}