#include <stdio.h>
int goal(int x, int y){
static int memo[99][99];
if(y==0 || x==y)
return 1;
else {
if(memo[x][y]!=0)
return memo[x][y];
else
return memo[x][y]=goal(x-1,y-1)+goal(x-1,y);
}
}
int main(void) {
int x,y;
return 0;
}
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