string = {}

string[0] = 'Li'
string[1] = 'Cs'
string[2] = 'H_'
string[3] = 'P-'
string[4] = 'CA'
string[5] = 'N_'
string[6] = 'H_'

ptval = {}
ptval['H_'] = '001'
ptval['He'] = '002'
ptval['Li'] = '003'




for element in string.iteritems():
	if element in ptval.keys():
		print ptval[element]