unittest
{
	assert( [ "a" ].parse.expand.solve == 'b' );
	assert( [ "y" ].parse.expand.solve == 'z' );
}



import std.conv;
import std.range;
import std.stdio;
import std.typecons;

void main()
{
	stdin.byLineCopy.parse.expand.solve.writeln;
}

auto parse( Range )( Range input )
if( isInputRange!Range && is( ElementType!Range == string ) )
{
	auto c = input.front.to!( dchar );
	return tuple( c );
}

auto solve( dchar c )
{
	return cast( dchar )( c + 1 );
}
