開頭自己補上

int main()
{
    int n,m,x;
    while(scanf("%d %d",&n,&m)!=EOF)
    {
        x=1;
        while((2*n+(x-1))*x<=2*m)
        {
            x++;
        }
        printf("%d\n",x);
    }

    return 0;
}