#include<stdio.h>
#include<math.h>
void perfect_square(int n)
{
    if ( n < 0) {
        printf("Invalid input\n");
        return 0;
    }
    int i = 1;
    while (i* i<= n) {
        printf("%d", i* i);
        i++;
    }
    printf("\n");
}

int main()
{
    int n;
    scanf("%d",&n);
    perfect_square(n);
    return 0;
}