public class NaturalNumber {
public static void main(String[] args) {
int sum = 0;
String str = "";
for(int i=1; i<=100;i++){
if(i%6 > 0 && i%7 > 0 && String.valueOf(i).indexOf("6") < 0 && String.valueOf(i).indexOf("7") < 0){
if(sum + i > 2000){
break;
}
sum += i;
str += i + "+";
}
}
str = str.substring(0, str.length() -1);
System.out.println(sum);
System.out.println(str + "=" + sum);
}
}
1979
1+2+3+4+5+8+9+10+11+13+15+19+20+22+23+25+29+31+32+33+34+38+39+40+41+43+44+45+50+51+52+53+55+58+59+80+81+82+83+85+88+89+92+93+94+95=1979