#include
                  int permutation(int n,int r);
                  int main(){
                    int n,r,p,c,f=1,y;
                    printf("n=");
                    scanf("%d",&n);
                    printf("r=");
                    scanf("%d",&r);
                    p=permutation(n,r);
                    if(p==0)
                    printf("math error");
                    else{
                    printf("P(%d,%d)=%d\n",n,r,p);
                      y=r;
                    for(;y>1;y--){
                      f*=y;
                    }
                    printf("C(%d,%d)=%d",n,r,p/f);}
                    
                    
                    
                    
                    return 0;
                  }
                  int permutation(int n,int r){
                    int permutation,x,y,f=1,z=1;
                    if(r>=0&&r<=n){
                      x=n;
                      y=(n-r);
                      for(;x>1;x--){
                        f*=x;
                      }
                      for(;y>1;y--){
                        z*=y;
                      }
                    return f/z;
                    }
                    else
                    return 0;	
                    
                  }