int a;
int b;
int c;

void F1(){
    b = a * 2;
    a = b;
}

void F2(){
    c = a + 1;
    a = c;
}

int main(){
    a = 5;
    // !!! Start F1(),F2() in parallel
    {
        F1(); 
        F2();
    }
    printf("%d\n", a);
}