View Compilation Error

0_0_8139469_22351.c: In function `main':
0_0_8139469_22351.c:3: error: `_int64' undeclared (first use in this function)
0_0_8139469_22351.c:3: error: (Each undeclared identifier is reported only once
0_0_8139469_22351.c:3: error: for each function it appears in.)
0_0_8139469_22351.c:3: error: syntax error before "n"
0_0_8139469_22351.c:4: error: `n' undeclared (first use in this function)
0_0_8139469_22351.c:4: error: `m' undeclared (first use in this function)
0_0_8139469_22351.c:8: error: `k' undeclared (first use in this function)