View Compilation Error

0_0_14175430_30093.cpp: In function 'int main()':
0_0_14175430_30093.cpp:8:28: error: 'n' was not declared in this scope
         scanf("%d%d%d%d", &n, &m, &p, &q);
                            ^
0_0_14175430_30093.cpp:8:32: error: 'm' was not declared in this scope
         scanf("%d%d%d%d", &n, &m, &p, &q);
                                ^
0_0_14175430_30093.cpp:8:36: error: 'p' was not declared in this scope
         scanf("%d%d%d%d", &n, &m, &p, &q);
                                    ^
0_0_14175430_30093.cpp:8:40: error: 'q' was not declared in this scope
         scanf("%d%d%d%d", &n, &m, &p, &q);
                                        ^
0_0_14175430_30093.cpp:13:13: error: 'ans' was not declared in this scope
             ans = k * q;
             ^
0_0_14175430_30093.cpp:14:61: error: 'min' was not declared in this scope
             printf("%d\n", ans + min((n-k*m)*p, (k*m==n)?0:q));
                                                             ^