#include <stdio.h>

int main(void)
{
    int N = 1;
    int A, B, C, X;
    scanf("%d %d %d", &A, &B, &C);
    while(1)
    {
        X = N * A - B;
        if(X <= 0)
        {
            if(N * A != C)
            {
                if(N == 1)
                {
                    printf("%d", -1);
                    break;
                }
                else
                {
                    N++;
                }
            }
            else
            {
                printf("%d\n", N);
                N++;
            }
        }
        else
        {
            if(X > C)
            {
                if(N == 1)
                {
                    printf("%d", -1);
                    break;
                }
                else
                {
                    break;
                }
            }
            else
            {
                printf("%d\n", N);
                N++;
            }
        }
    }
    return 0;
}