View Compilation Error

1_858_40_21547.cpp: In function 'int main()':
1_858_40_21547.cpp:21:25: error: 'mp' was not declared in this scope
                         mp[s1[i]]++;
                         ^
1_858_40_21547.cpp:25:28: error: 'mp' was not declared in this scope
                         if(mp[s2[i]]==0)
                            ^