View Compilation Error

0_0_18149449_8944.cpp:1:13: error: 'ans' does not name a type
             ans += (r - R) / M * mul;
             ^
0_0_18149449_8944.cpp:2:13: error: expected unqualified-id before 'if'
             if (R != 0)
             ^
0_0_18149449_8944.cpp:4:9: error: expected declaration before '}' token
         }
         ^