View Compilation Error

0_0_6253695_30281\Main.java:9: i is already defined in main(java.lang.String[])
        for (int i = 0; i < t; i ++) 
                 ^
0_0_6253695_30281\Main.java:18: cannot find symbol
symbol  : variable sum
location: class Main
                sum = sum.add(input);
                ^
0_0_6253695_30281\Main.java:18: cannot find symbol
symbol  : variable sum
location: class Main
                sum = sum.add(input);
                      ^
0_0_6253695_30281\Main.java:22: cannot find symbol
symbol  : variable sum
location: class Main
            System.out.println(sum);
                               ^
4 errors