View Compilation Error

220633_0_16590.c: In function `main':
220633_0_16590.c:14: error: stray '\' in program
220633_0_16590.c:14: error: `n4' undeclared (first use in this function)
220633_0_16590.c:14: error: (Each undeclared identifier is reported only once
220633_0_16590.c:14: error: for each function it appears in.)