View Compilation Error

0_0_33417691_24358.cpp: In function 'int main()':
0_0_33417691_24358.cpp:22:27: error: invalid initialization of reference of type 'int&' from expression of type 'long long int'
   int ans = ex_gcd(a,b,x,y);
                           ^
0_0_33417691_24358.cpp:4:5: note: in passing argument 3 of 'int ex_gcd(int, int, int&, int&)'
 int ex_gcd(int a, int b, int &x, int &y) {
     ^