command in if else loop repeat when I release button

Question

In blynk I create a virtual pin v4 and v5 and the minimum and maximum value of both is 0 and 1, In dashboard I have two push button,the first one link to v4 and the second one link to v5, and I use this code

int n;

BLYNK_WRITE(V4) 
{   
    int hit = param.asInt();   
    if (hit = 1)
    {
       n -= 1;
       Blynk.virtualWrite(V2,n);
       Serial.println(param.asInt());
    } 
} 
BLYNK_WRITE(V5) 
{   
    int hit = param.asInt();   
    if (hit = 1)
    {
       n += 1;
       Blynk.virtualWrite(V2,n);
       Serial.println(param.asInt());
    } 
}

when I press the first button(v4) hit become 1, n increase by 1 and serial print n, and when I release the button, hit become 0 but n still increase by 1 and serial print n instead of nothing happen, it also happen the same when I press and release the second button(v5). I don't know why, when hit become 0 but code in if loop still running. I what it to running only one time when I press the button.