#define S1 4
#define S2 5
#define S3 6
#define M1 8
#define M2 9
bool S1x,S2x,S3x;

void setup() {
pinMode(S1, INPUT_PULLUP);
pinMode(S2, INPUT_PULLUP);
pinMode(S3, INPUT_PULLUP);
pinMode(M1, OUTPUT);
pinMode(M2, OUTPUT);
}

void loop() {
S1x = !digitalRead(S1);
S2x = !digitalRead(S2);
S3x = !digitalRead(S3);

if((S1x and S2x)or(S2x and S3x)or(S1x and S3x))
digitalWrite(M1, HIGH);
if((S1x and !S2x and !S3x)or(S2x and !S1x and !S3x)or(S3x and !S1x and !S2x)){
digitalWrite(M2, HIGH);
digitalWrite(M1, LOW);
} else
digitalWrite(M2, LOW);
}