#include<stdio.h>
int main()
{
    int limit;
    scanf("%d", &limit);
    if (limit < 0) 
    {
        printf("Invalid input\n");
        return 0;
    }
    for (int i = 1;
    While (i* i <= limit)
    {
        printf("%d", i* i);
        i++;
    }
    printf("\n");
    return 0;
}