/*#include <stdio.h>
int main()
{
int i,n,a,sum=0;
scanf("%d",&n);
for(i=1;i<=n;i++)
{
scanf("%d",&a);
if(a%5==0)
{
sum=sum+a;
}
}
printf("%d",sum);
return 0;
}*/
/*#include <stdio.h>
int main()
{
int i,n,k,mul=1;
scanf("%d %d",&n,&k);
for(i=1;i<=k;i++)
{
mul=mul*n;
}
printf("%d",mul);
return 0;
}*/
/*#include <stdio.h>
int main()
{
int n,i,mul=1;
scanf("%d",&n);
for(i=1;i<=n;i++)
{
mul=mul*i;
}
printf("%d",mul);
return 0;
}*/
/*#include <stdio.h>
int main()
{
int a,b,i,sum=0;
scanf("%d %d",&a,&b);
for(i=a;i<=b;i++)
{
if(i%2==0)
{
sum=sum-i;
}
else
{
sum=sum+i;
}
}
printf("%d",sum);
return 0;
}*/
/*#include <stdio.h>
int main()
{
int a,d,n,i,sum;
scanf("%d %d %d",&a,&d,&n);
sum=a;
for(i=1;i<=n-1;i++)
{
sum=sum+d;
}
printf("%d",sum);
return 0;
}
*/
/*#include <stdio.h>
int main()
{
int a,r,n,i;
long long int mul;
scanf("%d %d %d",&a,&r,&n);
mul=a;
for(i=1;i<=n-1;i++)
{
mul=mul*r;
}
printf("%lld",(long long int)mul);
return 0;
}*/
/*
#include <stdio.h>
int main()
{
int a,m,d,n,i;
long long int mulsum;
scanf("%d %d %d %d",&a,&m,&d,&n);
mulsum=a;
for(i=1;i<=n-1;i++)
{
mulsum=mulsum*m+d;
}
printf("%lld",(long long int)mulsum);
return 0;
}
*/
/*#include <stdio.h>
int main()
{
int n,i;
scanf("%d",&n);
i=1;
while(i<=n)
{
printf("%d ",i);
i++;
}
while(n!=0)
{
printf("%d ",n);
if(n==5)
{
break;
}
n--;
}
return 0;
}*/
/*#include <stdio.h>
int main()
{
int n;
while(1)
{
scanf("%d",&n);
if(n==0)
{
break;
}
printf("%d\n",n);
}
return 0;
}*/
/*#include <stdio.h>
int main()
{
int n;
scanf("%d",&n);
while(n>0)
{
n=n-1;
printf("%d\n",n);
}
return 0;
}*/
/*#include <stdio.h>
int main()
{
int n,sum=0;
scanf("%d",&n);
while(n>0)
{
if(n%2==0)
{
sum=sum+n;
}
n--;
}
printf("%d",sum);
return 0;
}
복합대입연산자
i++ i=i+1
i=i-1 i--
i=i+2 i+=2
i=i/10 i/=10
#include <stdio.h>
int main()
{
int n,c=0;
scanf("%d",&n);
while(n!=0)
{
n/=10;
c++;
}
printf("%d",c);
return 0;
}
#include <stdio.h>
int main()
{
int a,b,c,d;
scanf("%2d%2d%2d-%d",&a,&b,&c,&d);
d=d/1000000;
if(d==1 || d==2) printf("%d",1900+a);
else printf("%d",2000+a);
printf("/%02d/%02d ",b,c);
if(d==1||d==3) printf("M");
else printf("F");
return 0;
}
*/
#include <stdio.h>
int main()
{
int n,i,sum=0;
for(i=1;i<=7;i++)
{
scanf("%d",&n);
if(n%2!=0)
{
sum=sum+n;
}
}
if(sum>0)
{
printf("%d",sum);
}
else
{
printf("-1");
}
return 0;
}