View Compilation Error

0_0_16144686_14844.cpp: In function 'int main()':
0_0_16144686_14844.cpp:24:21: error: 'MAXN' was not declared in this scope
             char s2[MAXN];  
                     ^
0_0_16144686_14844.cpp:43:21: error: 's2' was not declared in this scope
                     s2[cnt++]=s1[i];  
                     ^
0_0_16144686_14844.cpp:47:21: error: 's2' was not declared in this scope
                     s2[cnt++]=s1[i];  
                     ^
0_0_16144686_14844.cpp:61:20: error: 's2' was not declared in this scope
                 if(s2[i]=='f')  
                    ^