View Compilation Error

0_0_35301448_29804.cpp:15:1: error: 'l' does not name a type
 l gcd(ll a, ll b)
 ^
0_0_35301448_29804.cpp: In function 'int main()':
0_0_35301448_29804.cpp:58:22: error: 'gcd' was not declared in this scope
    ll d = gcd(up,down);
                      ^
0_0_35301448_29804.cpp:65:21: error: 'gcd' was not declared in this scope
   ll d = gcd(up,down);
                     ^