View Compilation Error

0_0_19184880_15082.cpp: In function 'int main()':
0_0_19184880_15082.cpp:40:8: error: 'ed' was not declared in this scope
    n = ed - st + 1;
        ^
0_0_19184880_15082.cpp:40:13: error: 'st' was not declared in this scope
    n = ed - st + 1;
             ^