#include <stdio.h>
#include <stdlib.h>
#include <math.h>

int main(int a, char *pole[]) {
   double f2, f1, deltaf, x, yz1, yz2, y, sum, sum1, p;
   int N, N1, c, k, n2, i;
   
   f2=0;
   f1=0;
   N=0;
   N1=0;
   c=0;
   k=0;
   deltaf=0;
   x=0;
   yz1=0;
   yz2=0;
   y=0;
   n2=0;
   sum=0;
   sum1=0;
   p=0;
    f1=atof(pole[1]);
    f2=atof(pole[2]);
    N=atoi(pole[3]);

    deltaf=f1/N;
    k=f2/deltaf;
    c=cos(2*M_PI*k/N);
    N1=N;

    
    while(scanf("%lf", &x) == 1) {
      while (n2<5){
        for (i = 0; i < N; i++){
          yz2=yz1 ;
          yz1=y;
          y=(yz1*2*c)-yz2+x; 
        }
        n2++;
        sum=(y*y)+(yz1*yz1)-(2*c*y*yz1);
        sum1=sum+sum1; 
      }
      sum1=sum1/5;
      for (i = 0; i < N; i++){
        yz2=yz1 ;
        yz1=y;

        y=(yz1*2*c)-yz2+x;
      }
      n2++;
      p=(y*y)+(yz1*yz1)-(2*c*y*yz1);
    }
        
    if (sum1>p){
        printf("-");
    }
    else{
        printf("+");
    }

      printf("\n");
      return 0;
}