#include<stdio.h>
int main ()
{
    int a,b,c;
    scanf("%d %d %d", &a, &b, &c);
    if(a<=0||b<=0||c<=0||a)
    printf("invalid input\n");
    return 0;
}
if(a + b <= c || a + c <= b || b ++)
{
printf("invalid input\n");
return 0;
}
if (a == b && b == c)
{
    printf("equilateral\n");
}
else if(a==b||b==c||a==c)
printf("isosceles\n");
}
else
{
    printf("scalene\n");
}
return 0;
}