C Program to check valid triangle using nested if

#include<stdio.h>
int main()
{
	int side1, side2, side3;
	
	/* Initially assume that the triangle is not valid then create a Flag*/
	int flag = 1;
	
	printf("Enter three side of Triangle: ");
	scanf("%d%d%d",&side1,&side2,&side3);
	
	
	if((side1 + side2) > side3 )
	{
		if((side2 + side3) > side1)
		{
			if((side1 + side3) > side2)
			{
				/* If all condiction is satisfied then flag is true or 1 */
				
				flag = 1;
			}
		}
	}
	
	if(flag == 1)
	{
		printf("Triangle is Valid");
	}
	/* If Flag is 0 or Flase */
	else
	{
		printf("Invalid Triangle");
	}
	
	return 0;
}

Output

Enter three side of Triangle: 10
12
15
Triangle is Valid