View Compilation Error

0_0_16830081_5055.cpp: In function 'int main()':
0_0_16830081_5055.cpp:22:9: error: 'llu' was not declared in this scope
         llu n;
         ^
0_0_16830081_5055.cpp:23:24: error: 'n' was not declared in this scope
         scanf("%I64u",&n);
                        ^
0_0_16830081_5055.cpp:24:13: error: expected ';' before 'output'
         llu output=n;
             ^
0_0_16830081_5055.cpp:27:30: error: 'output' was not declared in this scope
             printf("%I64u\n",output);
                              ^
0_0_16830081_5055.cpp:32:13: error: 'output' was not declared in this scope
             output+=n*(n-1)/2*(n-2)/3*(n-3)/4;
             ^