Unable to solve Input output test case using C program

I am trying to solve a simple C program using Replit and solve a test case which reads two inputs and calculate the sum. But the testcase is failing all the time I execute the program.

int main()
int a,b,c;
scanf("%d%d", &a,&b)
return 0;

I am getting this error when I run the program.
::error::The output for test aaa did not match%0AExpected:%0A3%0AActual:%0Amake: Nothing to be done for ‘aa.c’.
Can anyone please help me in solving this error? or Let me know if there are any configurations to be done ?