Main.c: In function 'main':
Main.c:25:18: error: expected '=', ',', ';', 'asm' or '__attribute__' before '-' token
   25 |             int u-0;
      |                  ^
Main.c:25:18: warning: statement with no effect [-Wunused-value]
Main.c:31:17: error: 'u' undeclared (first use in this function)
   31 |                 u=p[3*i];
      |                 ^
Main.c:31:17: note: each undeclared identifier is reported only once for each function it appears in