View Compilation Error

0_0_36689384_4015.cpp: In function 'int main()':
0_0_36689384_4015.cpp:9:30: error: 'sqrt' was not declared in this scope
    for (int j = 1; j <=sqrt(a); j++) {
                              ^
0_0_36689384_4015.cpp:16:31: error: 'sqrt' was not declared in this scope
    for (int j = 1; j <= sqrt(b); j++) {
                               ^